Hi,
Support center gave me the answer.
We set the state of each DNS server to "NO INFO" when adding it to the list of servers to use.
Later, we would set the state to DOWN if there was problems communicating with server, or UP if we interacted with it successfully.
So when you see NO INFO, we simply have not yet had reason to connect to that particular DNS server.
-so the other server must have been resolving all requests the filer needed to get resolved.
Hence what you currently see is not a problem